E30 Suspension upgrade advice please

[jsabatini]

I am finally upgrading the suspension on my '90 325is. Presently have the stock 14" basket weave wheels with Yoko AVSES100 in 205/60 fittiment. Would like to upgrade to 15" wheels in the future.

I am thinking about either:

H&R Cup Kit shocks and springs which lower the car 2.1F & 1.7R

or

Koni Sport shocks with either Eibach Pro springs (1.6F & 1.4R) or H&R Sport springs (1.3F&R)

Also going with H&R Anti-roll bar kit (27mm F & 18mm R)

Any advice or pros and cons with either set up. With the extreme lowering of the H&R Cup Kit will I have any rubbing problems? Car is my daily driver and about 6 - 10 track days per year. I am an instructor with both BMWCCA and PCA at Sebring, Moroso, and Road Atlanta.

[Spencer]

From what I've heard, the E30 cup kit is too soft for its ride height. You'll be riding the bump stops on the track.

I think option 2 (with either spring) is going to be your better option.

[ydubbs4]

H&R Sports are stiffer than the Eibachs, I would go that route.

[Erik@EDGE]

Given that you are doing as many events as you are and that you are an instructor (thus I assume you know how to drive well enough to appreciate good suspension) I would recommend against all of your options and recommend that you consider a Ground Control setup. You can play with the spring rates to get the ride you desire, and in the end you can fine tune your car to your liking....something you can't do with any of your mentioned options.

If you need more info on setup, give us a call. Rich had a very competitive e30 with GC suspension, and we run variations of it on many, many customer cars.

[PeteinMD]

I have Koni SAs with H&R sport springs, RD sways, urethane bushing, etc. While the car is incredibly balanced, I can hit the bump stops in turns. The H&R springs are not harsh; if they are stiffer than Eibach, I would definitely forget the Eibach springs.

I'm running in the advance group in DEs, with some thoughts of club racing in the future.

I'd suspect the Bilstein/H&R setup is just about the same for stifness.

Best,


PeteinMD
'00 M coupe
'90 325i

[wludavid]

From what I've heard, the Cup Kit isn't a serious set-up. More like bolt on kit for those that just want a lowered look... not that there's anything wrong with it. It's just probably not the way to go for the track.

I've got Koni SA's and H&R Sport. I like it for the street, but I haven't done any tracking yet.

[randywalters]

I am finally upgrading the suspension on my '90 325is. Presently have the stock 14" basket weave wheels with Yoko AVSES100 in 205/60 fittiment. Would like to upgrade to 15" wheels in the future.

I am thinking about either: H&R Cup Kit shocks and springs which lower the car 2.1F & 1.7R or Koni Sport shocks with either Eibach Pro springs (1.6F & 1.4R) or H&R Sport springs (1.3F&R) Also going with H&R Anti-roll bar kit (27mm F & 18mm R)

Any advice or pros and cons with either set up. With the extreme lowering of the H&R Cup Kit will I have any rubbing problems? Car is my daily driver and about 6 - 10 track days per year. I am an instructor with both BMWCCA and PCA at Sebring, Moroso, and Road Atlanta.

None of those spring setups will be stiff enough for track use. You'll need much stiffer spring rates than those kits have. Also, Bilsteins won't have nearly enough rebound damping for stiff racing springs so go with Koni single or double adjustables. And keep the rear swaybar on the small side so both sides and work independently. Big front bar is ok though. You'll also need camber plates or KMac adjustable strut mounts up front. Also, lowering the car too much reduces cornering grip in the rear due to limits of the rear suspension geometry. I had to raise the rear to get more grip out back.

[Halon]

higher than stock in the rear? @_@ I must have not read this very carefully.

[E30 Racer]

I am finally upgrading the suspension on my '90 325is. Presently have the stock 14" basket weave wheels with Yoko AVSES100 in 205/60 fittiment. Would like to upgrade to 15" wheels in the future.

I am thinking about either:

H&R Cup Kit shocks and springs which lower the car 2.1F & 1.7R

or

Koni Sport shocks with either Eibach Pro springs (1.6F & 1.4R) or H&R Sport springs (1.3F&R)

Also going with H&R Anti-roll bar kit (27mm F & 18mm R)

Any advice or pros and cons with either set up. With the extreme lowering of the H&R Cup Kit will I have any rubbing problems? Car is my daily driver and about 6 - 10 track days per year. I am an instructor with both BMWCCA and PCA at Sebring, Moroso, and Road Atlanta.

You shouldn't have any rubbing issues with your 205/60-14s with even extreme lowering. When you upgrade to 15s, you should be OK as well, just as long as you're realistic about your wheel/tire selection. The 15x7.5 Ronal/ACT basketweaves Randy uses are about as wide as I'd go for wheels, and with 225/50-15 street tires, you'll have a nice balance of looks and performance without having to maul your car.

15x8s are OK as well, but you may need to limit your tire selection to 205/50-15 unless you're willing to roll the fenders a bit. Depending on which wheels you select, you may have to use spacers at the front.

If you're planning to use R- or A-compound tires (i.e., a Hoosier), be aware they tend to run a bit wider than their sidewall description indicates.

As far as your suspension questions go, here's my 2-cents.

1. The suspensions you listed are nice, reasonably sorted street suspensions. Simply lowering the car a lot does not necessarily make it a terror on the track.

2. Personally, I'd take a hard look at what Ground Control has to offer. Although more expensive than the options you've listed, I think you'll ultimately be happier with the GC setup. One of the really nice things about adjustable coilovers is that *you* get to set your own ride height, and *you* get to select your own spring rates. Do a little research into what rates others are using, weigh the stiffness vs. streetable vs. intended use issues, talk to Jay, and make a selection. If you're unhappy with the result, no big deal. Sell your old springs on the boards or eBay and buy some new ones. They're about $60-70 each if purchased new.

3. Despite what the Tire Rack's website says, H&R does not make a 27mm front bar. This is a typo, the bar is really 22mm like everyone elses.

4. I'd advise against mongo swaybars until you've sorted your spring rates. You may find the stock ones work fine for you. If you choose big bars make sure you install reinforcements as the E30 front subframe, and both rear attachment points are weak and can fail quickly.

Good luck!

[vodomagoo]

ever consider j stock suspension? simple easy to set up suspension that is well proven. turner and bimmerworld both sell set ups. for rims go with 15x7 koseis, cheap and they fit great. on my car i run h&r coilovers with 580 and 680 spring rates and ireland engineerings big sway bars, the smaller ones are fine and you dont nessicarly need to go all that big

[randywalters]

higher than stock in the rear? @_@ I must have not read this very carefully.

I had lowered my car too much and found the resultant negative rear camber was excessive and was causing poor handling. I raised the rear a little to improve the camber to increase rear grip. It worked great.

[PeteinMD]

I've just been to a very reputable mechanic/racer about suspension ideas. Botom line, he indicated to wait until the money was there, then go with Ground Control. He races ITS, I'm just doing driver's schools, and possibly club racing late next year.

Hmph. Was hoping H&R + Koni/Bilstein was the ticket... btw, I'm running 16" wheels - came with car. No rubbing issues most of the time; rubs in front when wheel turned over fully in parking lot.

Best,

PeteinMD
'00 M coupe
90 325i

[E30 Racer]

I had lowered my car too much and found the resultant negative rear camber was excessive and was causing poor handling. I raised the rear a little to improve the camber to increase rear grip. It worked great.

Given that negative camber increases as rear ride height decreases, and negative camber generally improves grip, how can this be so? Were you running into coil bind issues? What are your rear spring rates? What is your front-to-rear tire pressure differential? Your lack of rear grip may attributable to many other factors than ride height...

[Rigmaster]

jsabatini + PeteinMD,

have you guys considered going with the SpecE30 setup?? Basically H&R race springs + Bilstein sport struts/shocks with any swaybar that meets the size requirements (I think it's 22/19mm). Mods are kept to a minimum in an effort to keep costs down, the fields are growing larger at every race, especially in the SE region (NC/VA in particular).

Check out www.spece30.com for rules + details.

I believe BMWCCA is going to recognize the SpecE30 class next season too, so you could race in CCA club racing as well as NASA racing with a SpecE30 car.

I'm not gonna say that the SpecE30 suspension setup is the "best", but I think it's a good solid setup, and once the car is properly setup, you have alot of opportunites to race in this class. And, the racing I've seen so far has been some of the best, close competition with pretty much equally prepared cars!

Bret.

[PeteinMD]

Bret,

I sure have considered a SpecE30 setup. However, my car came with other mods (bushings, chip, strut bars, ssk) and I don't feel like de-contenting it, to tell you the truth. As it is, I have H&R sport springs, and ride on the bump stops through Summit's up hill Esses - figure I need more spring, at least...

If I do decontent car, I'd be interested in Sped E30 in a heartbeat - bought the car before I knew it existed/understood the rules.

Best,

PeteinMD
'00 M coupe
'90 325i